Problem: Simplify the expression. $(5k-8)(5k+1)$
Explanation: First distribute the ${5k-8}$ onto the ${5k}$ and ${1}$ $ = {5k}({5k-8}) + {1}({5k-8})$ Then distribute the ${5k}.$ $ = ({5k} \times {5k}) + ({5k} \times {-8}) + {1}({5k-8})$ $ = 25k^{2} - 40k + {1}({5k-8})$ Then distribute the ${1}$ $ = 25k^{2} - 40k + ({1} \times {5k}) + ({1} \times {-8})$ $ = 25k^{2} - 40k + 5k - 8$ Finally, combine the $x$ terms. $ = 25k^{2} - 35k - 8$